Green’s Dictionary of Slang

an undergarment that combines camisole and knickers.

1938

194019451950

1952

1938		J. Curtis They Drive by Night 57: She would ask this geezer for half a quid. If he come across she’d be able to buy a new pair of cami-knicks.
1952		D. Thomas ‘The Followers’ in World Rev. Oct. 41/1: In a shop-window, two girls undressed the dummies. [...] ‘Mind her cami-knicks, Edna...’.